Product category:
Power Supply ICs and Controllers
News Release from: National Semiconductor | Subject: LM2770, LM2788, LM2797 and LM2798
Edited by the Electronicstalk Editorial
Team on 18 March 2005
No inductors required for buck
convertors
Four new step-down DC/DC convertors for portable systems feature a dynamic-gain architecture that provides up to 90% efficiency in a very small, inductor-free footprint.
National Semiconductor has released four new step-down DC/DC convertors for portable systems The buck convertors feature a dynamic-gain architecture that provides up to 90% efficiency in a very small, inductor-free footprint
This article was originally published on Electronicstalk on 5 Jan 2001 at 8.00am (UK)
Related stories
Dual-port Gigabit Ethernet transceiver
National Semiconductor has announced the DP83862, a low-cost, highly integrated dual-port 10/100/1000 physical layer transceiver.
World's smallest multifunction supervisory ICs
National Semiconductor has announced a family of supervisory ICs with a variety of factory-programmable features that can be configured in hundreds of possible combinations.
These devices power application circuits in portable devices including wireless handsets, digital still cameras, MP3 players, PDAs, hard disk drives, wireless LAN and other low-power, small form-factor products.
The LM2770, LM2788, LM2797 and LM2798 DC/DC convertors feature output currents up to 250mA over the extended Li-ion battery range of 2.7 to 5.5V.
The unique dynamic-gain architecture provides efficiency up to 90%, which is comparable to traditional buck regulator solutions that require external inductors.
Further reading
Leadless leadframe package shrinks LDO
National Semiconductor has introduced a full-featured 500mA LDO regulator for medium-current applications in computing devices and portable products.
Boomer shrinks stereo headphone amplification
New from National Semiconductor, the LM4811 Boomer audio amplifier is a 105mW stereo headphone amplifier for use in 3 and 5V systems requiring a headphone output and volume control.
Frugal dual-channel A/D conversion
National Semiconductor has introduced a dual-channel 8bit A/D convertor with record low-power dissipation levels.
A choice of two tiny packages along with four small ceramic capacitors and no external inductor provides the engineer with an extremely compact footprint that minimises board space and optimises the bill of materials.
The LM2770 also features user-selectable output voltages for increased flexibility of design and a low-power, low-dropout sleep mode that reduces the quiescent current and dramatically improves standby times.
The LM2797 and LM2798 feature input and output voltage monitoring that prevents unexpected power loss and instability issues during operation.
"Top mobile phone manufacturers rely on National Semiconductor to provide solutions that deliver the ideal combination of efficiency and size", said Peter Henry, Vice President of National Semiconductor's Portable Power Products Group.
"National's new DC/DC convertors maximise performance and minimise the solution footprint to offer unparalleled portable power solutions".
The LM2770 is a regulated switched capacitor step-down DC/DC convertor with an output current capability of 250mA over an input range of 2.7 to 5.5V.
It is available in fixed output voltage options of 1.2, 1.5 and 1.6V.
The LM2770 has a low-power sleep mode that limits the quiescent current to 30uA and significantly extends standby times.
Pin-selectable output voltages provide flexibility for system design.
The LM2770 is available in a miniature 10-pin, nonpullback LLP package.
The LM2788 is a regulated switched capacitor step-down DC/DC convertor with an output current capability of 120mA over an input voltage range of 2.6 to 5.5V.
The LM2788 is available in fixed output voltage options of 1.5, 1.8 and 2.0V.
The device uses multiple fractional voltage-gain steps to maximise power efficiency over the entire input voltage and output current ranges.
The low supply current of 32uA further contributes to long standby operation.
The LM2788 is available for simulation on National Semiconductor's award winning Webench tool on the company's website.
The LM2797 and LM2798, with the same features as the LM2788, also include input and output voltage-monitoring characteristics.
One signal monitors the battery and indicates when the input voltage falls below 2.85V and another pin verifies that the output voltage is no more than 5% below the nominal output voltage of the part.
The LM2797 has a faster turn-on time of 100us.
Each is packaged in a small MSOP-10.
Available now and priced in 1000-unit quantities, the LM2770 is $1.40, the LM2788 is $1.00, and the LM2797 and LM2798 are each $1.10.
• National Semiconductor: contact details and other news
• Email this article to a colleague
• Register for the free Electronicstalk email newsletter
• Electronicstalk Home Page
Search the Pro-Talk network of sites
